A grass spikelet

Grass inflorescences are made up of spikelets arranged in a various kinds of spikes, racemes or panicles.

Each spikelet has (with some very rare exceptions) two glumes, which are bracts that usually protect and enclose the flowers, placed below a series of flowers arranged in a zig-zag pattern. Each flower has two bracts, called the lemma and palea, which usually enclose the single remainder of the flower.

The flowers may be hermaphrodite (with one ovary and two or three stamens), male, female or completely lacking in sex organs (these are called sterile flowers and can often be only recognised by the presence of lemmas). There may be one, two or many flowers. It is critically important to determine how many flowers there are per inflorescence, and which parts are glumes, lemmas and paleas. 

The lemmas, paleas or glumes of many species have awns, which are elongated protruberances that are often like stiff hairs. These may be attached to the tip or the back of lemmas, or less often glumes or paleas. Some species have more than one awn on each lemma.